The invention relates to a multi-access multi-spot reconfigurable transmission antenna.
In the general case of space missions, the trend towards satellite transmissions to low-capacity users requires increasing the reception quality of the on-board equipment. This increase in capacity is obtained by increasing the gains of the on-board antennas, and this has the effect of reducing their coverages.
In order to provide continuity of service, these reductions in coverage require a plurality of beams to be generated. Such multi-spot coverage enables the on-board capacities to be managed better as a function of:
different traffic densities; and of PA1 changes in traffic densities over time.
For a satellite system providing world coverage, it is advantageous for it to be possible to replace a satellite that is defective or at the end of its life with a satellite taking up another orbital position. This requires multi-spot coverage that is reconfigurable.
Active antennas of the type having directly radiating arrays or focal arrays solve such problems of coverage reconfigurability and of capacity exchange between spots. However, such antennas suffer from the drawback of being very complex. Furthermore, they only provide limited reconfigurability and power exchange.
French Patent Application number 8803547 filed on Mar. 8, 1988 describes an antenna which provides electronically reconfigurable transmission and which comprises a reflector for energy focussing, an array of source elements situated in the focal region of the reflector, feed and control electronics including first and second generalized couplers disposed on respective sides of a plurality of amplifiers, and beam-forming circuits each corresponding to one transmitted beam; the amplitudes and the relative phases of the signals output by the circuits being controlled respectively by an adjustable attenuator and by an adjustable phase-shifter.
This type of solution suffers from the drawback of having limited reconfigurability for the spots generated by distinct sources or distinct groups of sources.